In the Oracle Enterprise Manager Reports Server’s Failed jobs we can see this error message:

Terminated with error:
REP-110: Unable to open file 'repenv1012.rdf'.
REP-1070: Error while opening or saving a document.
REP-0110: Unable to open file 'repenv1012.rdf'.

This error is due to the length of the REPORTS_PATH environment variable defined in $ORACLE_HOME/bin/reports.sh. We have a lot of applications deployed within one reports server, and the reports path length has exceeded 1024 chars.
To solve it, we have two ways: